Marking instrument



FIG. 1 is a side elevational view of a marking instrument, in an exploded condition, showing our new design, the opposite side being a mirror image thereof;

FIG. 2 is a front elevational view in an exploded condition;

FIG. 3 is a rear elevational view with the cap member omitted for convenience of illustration;

FIG. 4 is a bottom plan view with respect to FIG. 3; and

FIG. 5 is a top plan view with respect to FIG. 1. 

The ornamental design for a marking instrument, as shown and described. 